Evaporator having a heating element in unit relation therewith



Nov. 14, 1961 w. A. COLLINS 3,008,304

EvAPoRAToR HAVING A HEATING ELEMENT IN UNIT RELATION THEREwITH TOF/V173.

2 Sheets-Sheet 2 if f@ umn/J muy@ Nov. 14, 1961 w. A. COLLINS EvAPoEAToE HAVING A HEATING ELEMENT 1N UNIT RELATION THEREWITH Original Filed Aug. 14, 1953 QW 22E@ im United States Patent Oli-ice 3,008,304 Patented Nov. 14, 1961 v `This invention relates to evaporators, and particularly -to an evaporator having a defnosting heating element secured thereto, and is a continuation of Serial No. 374,- 366, filed August 14, 1953, now abandoned.

The evaporator of the present invention is formed from a tube bent to provide straight portions joined by end loops-. yThe tube is disposed in intimate contact with the v metal plates forming the walls of the evaporator so as to be inf good heat-conducting relationship therewith. The fluid employed in the evaporating system is passed through the sinuously formed sections of the tube for cooling the evaporator and the food contained therein. To produce 'the defrosting of the tube and walls of the evaporator, a lheating element is provided having a resistance element enclosed in a sheath and formed n a manner to follow the'sinuous form of the tube so that it may be disposed 1n intimate contact therewith when secured directly to the evaporator wall.

-It is within the purview :of the present invention to apply the sheath of a heating element directly to a sinuously fonmed tube which is employed as a crossover tube for joining the top and bottom tubular sections of an -evaporator when disposed adjacent to one of a pair of side -walls` which space Vthe sections apart. On the opposite j-fside wall ofthe evaporator, where no crossover tube is employed,the sinuously formed sheath of a heating elefrnentmay be welded, brazed or 'otherwise secured directly thereto.- In any of the constructions above referred to or in a combination thereof, a desired amount of heat may be provided directly to the walls for rapidly heating and defrosting the evaporator.

Accordingly, the main objects of the invention are: to provide a heating element for an evaporator which has a metal sheath directly secured thereto; to provide a heating element for an evaporator which is sinuously formed to follow the sinuous path of the refrigerant when secured to the wall of the evaporator directly adjacent thereto; to provide a heating element for the crossover tube of an evaporator, `the sheath of which is directly secured to the tube along the sinuous form thereof, and in general, to provide an evaporator having sinuous lengths of tubing, with the sheath of a heating element secured adjacent thereto which is simple in construction, efficient in operation and economical of manufacture.

Other objects and features of novelty of the invention will be specifically pointed out or will become apparent when referring, for a better understanding of the invention, to the following description taken in conjunction with the accompanying drawings, wherein:

FIGURE l is a broken plan view of an evaporator ernbodying features of the present invention;

FIG. 2 is a front view in elevation of the evaporator illustrated in FIG. l;

FIG. 3 Iis a broken view of the evaporator illustrated in FIG. l, as viewed from the left-hand end thereof;

FIG. 4 is a broken view of the evaporator illustrated in FIG. l, as viewed from the right-hand end thereof;

FIG. 5 is a bnoken view of an end of the evaporator, similar to that illustrated in FIG. 4, showing a modified form thereof, and

FIG. 6 is a broken view of an evaporator, similar to that illustrated in FIG. 3, showing a further form which the invention may assume.

Referring to FIGS. l to 4, an evaporator is illustrated made from an upper plate 10, a lower plate 12 and two supporting side walls 13 and 14. A tube 15 is sinuously formed to provide straight portions 16 joined by end loops 17. The tube thus formed is welded, brazed or otherwise secured to the plate 12 in intimate heat-transfer relationship thereto. The plate 10 has a similar length of tube 21 sinuously formed to provide straight portions 22 joined by end loops 23 secured thereto. A recess 24 in the plate 10 receives an accumulator 25 which is supported therein by a suitable clip 26. A length of tube 27 joins the inner end of the tube 15 of the plate 12 to one end of the accumulator 25, An angleshaped tubular end portion 28 is joined to the opposite end of the accumulator and is extended along the side of the evapo rator, having an enlarged end 29 by which the end is connected to the tubular end of the refrigeration circuit.

A U-shaped length of tube 31 joins the end 32 of the tube 15 of the plate 12 with the end 33 of the tube 21 lof the plate 10. The U-shaped tubular element forms a crossover tubular section which permits the fluid to pass from the tube 2 of the plate 10 to the tube 15 of the plate 12. The present evaporator construction is similar to that illustrated, described and claimed in the copending application of W. A. Collines et al., Serial No. 337,762, filed February 19, 1953, now Patent 2,847,194, issued August l2, 8, and assigned to the assignee of the present invention. In such an arrangement, the plates 10 and 12 may be spaced any desired degree apart, depending upon the length of the side walls 13 and 14. The side walls 13 and 14 are turned inwardly at the bottom at 35 and overlap with the ends of the plate 12 and are welded or otherwise secured thereto. The top plate 10 is provided with side flanges 36 which engage and are welded to the side walls 13 and 14. The upper ends of the plates are flanged inwardly at 37 to provide supporting means by which the evaporator may be attached to the interior of a refrigerator.

The novely of the present invention resides in the application of heating elements to the plates 10 and 12. The heating elements 41 are of a type having a resistance element mounted within a tubular sheath `42. Terminals 43 are insulated from the ends of the sheath `42 and are joined to the resistance element within the sheath. AS illustrated more speciiically in FIG. l, the heating element 41 is sinuously formed in a manner to follow the form of the tube 15 and 21. Thus, it will be noted that straight portions 44 of the sheath 42 are disposed closer together by the end loops 45 than the straight portions 44 are spaced by the end loops 46. This is necessary as the end loops 45 are disposed inside of a loop 17 or 23 of the tube, while end loops 46 are disposed on the outside of the loops 17 and 23. The sheath formed in this manner when brazed, welded or otherwise secured to the plate and/ or the tube, is in direct heat-conducting relationship therewith and with the fluid therewithin so that the rapid heating of the tube and plate quickly defrosts the evaporator. The terminal ends 43 of the heating elements on the top and bottom plates 10 and 12 in the example illustrated are disposed in aligned relation along the side walls 13 and 14 so that they may be directly connected into an electric supply circuit.

When a greater heating capacity is desired than that provided by the heating elements 41 additional heating elements -Inay be applied to the side Walls 13- and 14 of the evaporator. In FIG. 5 a heating element 51, similar to the heating element 41, is directly secured to the side wall 14. Such a heating element may be employed alone or additionally with one or both of the heating elements 41 secured to the plates 10* and 12.

In FIG. `6 the crossover tubular element 31 is illustrated as embodying a length of tube 52 of sinuous form joined to the ends 32 and 33 of the tubes 15 and 2x1. A heating element 53, of such sinuous `form as to follow the form of the tube 152, is welded, brazed or otherwise secured directly thereto. A bracket 54 secures the sheath and tube in engagement with the side wall 13` across which they extend. Similar clips 55 may be employed for securing the tubes 27 and 28 to the plate 10 so as to have the tubes in fixed relation thereto.

It is to be understood that a single heating element 41 may be applied either to plates 10 or 12 or to both plates, as illustrated. A heating element 51 may be applied to the side 14 of the evaporator or a heating element 53` may be secured to the sinuously formed crossover element 5-2 at the side '13 of the evaporator. It is to be understood that any combination of heating elements may be emplayed, depending upon the type of evaporator and the amount of heat required for the defrosting operation. In `other words, either or both of the heating elements 51 and 53 may be employed alone or with one or both of the heating elements 41 of the plates 10 and 12.

What is claimed is:

1. An evaporator for a refrigerating unit having spaced walls, a continuous refrigerant tube disposed on at least two of said walls with portions thereof on each wall formed in a sinuous pattern having straight sections in side-by-side relation with a rst set of end loops joining the straight sections at one end thereof and a second set of end loops joining the straight sections at the other end thereof, a pair of heater elements, each of said two walls having a heating element disposed thereon adjacent to the sinuous tube portions thereof, each of said heating elements being encased in a solid impervious tube made of brazable material and formed into a sinuous pattern having straight sections joined by one group of end loops wider than said first set of end loops and joined at the other end by another group of end loops narrower than said second set of end loops, each `of said heating elements nesting with said sinuous portions of the refrigerant tube in co-planar relationship with said one group of end loops fitting closely around said first set of end loops and said other group of end loops fitting closely within said second set of end loops, and brazing material brazing the nested heating elements and refrigerant tube portions directly to one another and to the walls on which they are disposed.

2. An evaporator for a refrigerating unit having spaced walls, a continuous refrigerant tubeA disposed on at least two `of said walls with portions thereof on each wall formed in a sinuous pattern having straight sections in side-by-side relation with a first set of end loops joining the straight sections at one end thereof and a second set of end loops joining the straight sections at the other end thereof, a heater element disposed on at least one of said two walls adjacent to the sinuous tube portions thereon, said heating element being encased in a solid impervious tube made of brazable material and formed into a sinuous pattern having straight sections joined by one group of end loops wider than said first set of end loops and joined at the other end by another group of end loops narrower than said second set of end loops, said heating element housing with said sinuous portions of the refrigerant tube in co-planar relationship with said one 'group of end loops tting closely around said first set of end loops and said other group of end loops fitting closely within said second set of end loops, and brazing material brazing the nested heating element and refrigerant tube portions directly to one another and to the wall on which they are disposed.

References Cited in the file of this patent UNITED STATES PATENTS 1,127,373 Read Feb. 2, 1915 2,601,466 Thomas June Z4, 1952 2,637,180 Atchison May 5, 1953 2,685,634 Bartlowe Aug. 3, 1954 2,749,717 Duncan June 12, 1956 2,758,150v Zargarpur Aug. 7, 1956 

